Spinning solutions of vinyl chloride polymer dissolved in a solvent mixture containing tetrahydrofurane and an additional solvent selected from the group consisting of lactones and lactams



Patented Nov. 4, 1952 SPINNING SOLUTIONS OF VINYL CHLORIDE POLYMER DISSOLVED IN A SOLVENT MIX- TURE CONTAINING TETRAHYDROFURAN E AND AN ADDITIONAL SOLVENT SELECTED FROM THE GROUP CONSISTING OF LAC-; TONES AND LACTAMS Erwin Heisenberg, Erlenbach-on-the-Main, and Johannes Kleinc, Munchen, Germany, assignors to Vereinigte Glanzstofi-Fabriken A. G., Wuppertal-Elberfeld, Germany, a German firm No Drawing.

Application April 18, 1951, Serial No. 221,713. In Germany August 18, 1949 8 Claims. (01. zoo-30.2

The present invention relates to liquid compositions of matter, more especially solutions of polymers and/or copolymers of vinyl chloride, which can be spun to form threads and the like and which can be cast to form films. The invention relates further to the production of such compositions and to the production of spun filaments with the aid thereof.

It has been proposed in the literature to dissolve polyvinyl chloride in tetrahydrofurane and to work up these solutions into artificial threads. In this way, however, solutions are obtained of gluey'consistency which in practice cannot be spun.

Attempts have been made to overcome this disadvantage by subjecting the polyvinyl chloride to an additional chlorination before dissolving it. This does give an increased'solubility, for example even in acetone, but such a procedure means that the process involves an additional step. a

Even when the spinning properties are improved by heating the solutions before spinning, for example to 50 0., and even when spinning is carried out at this temperature, a satisfactory result is not obtained. Moreover, when working in the vicinity of the boiling point of the solvent, bubbles are readily formed in the thread which considerably reduces its quality. The thread is also embrittled by spinning at raised temperature so that optimum strength values are no longer obtained upon subsequent stretching.

A whole series of lactones and lactams have been proposed in the patent literaturewhich are said to be suitable as solvents for high polymers and copolymers of vinyl compounds. Such solvents or mixtures thereof, however, do not give solutions which can be used to spin threads of high quality.

In order to increase the solubility of polyvinyl chloride, certain quantities of other vinyl compounds have been added during polymerization. It has in fact been possible to increase the solubility of polyvinyl chloride in this way, but only at the cost of imparting inferior textile properties to the spun threads prepared therefrom.

A primary object of the present invention is the embodiment of spinning solutions which are free of the prior art defects as hereinbefore set forth. A further object of the invention is the preparation of spun polymeric or copolymeric vinyl chloride filaments of improved physical properties and manifestly superior textile properties, and which can be further conditioned to produce superiortextile-fibers." These objects are 2 V achieved in a simple way according to the present invention, with production of good spinning solutions of vinyl chloride polymers and copolymers from which high quality threads can be spun, by incorporating into the tetr-ahydrofurane, which is used as solvent, certain quantities of butyrolactone. The results thus achieved are surprising because neither tetrahydrofurane nor butyrolactone by itself gives vinyl chloride polymer solutions which can be satisfactorily spun. The favorable influence of butyrolactone becomes perceptible even on addition of about 10% by weight, relative to the weight of the solvent mixture, and increases with increasing quantity of the addition. The effect begins to diminish only when the butyrolactone becomes the predominant component of the mixture. A particularly favorable proportion of the two said compounds in the mixture is a proportion of one part by weight of butyrolactone to three parts by weight of tetrahydrofurane.

Moreover, admixture with tetrahydrofurane ac cording to the invention produces a fundamental change not only in the solvent power of butyrolactone but also in the solvent power of other solvents which have previously been proposed for polyacrylonitrile but which by themselves cannot be used to give vinyl chloride polymer solutions which can be satisfactorily spun. Such compounds which can be used with tetrahydrofurane as solvents to give vinyl chloride polymer solutions which can be satisfactorily spun according to this invention comprise other lactones as well as lactams and other chemical compounds of analogous structure, such for example as:

Glycol carbonate; 'y-Valerolactone; N-phenylpyrrolidone; N-methylpyrrolidone;

Diglycolide; a-Piperidone (a-valerolactam') a-Pyrrolidone -butyrolactam); 3-hydroxy-2-pyrrolidone; 4-hydroxy-2-pyrrolidone; N-fOllIlYL-l-DIDEIIdODG; e-Caprolactam;

sz-Heptolactam N-isopropyl-pyrrolidone; 'y-Caprolactoney a-Ethylbut'yrolactone; at,-Dimethyl-butyrolactone; -Isobutyl-butyrolactone; a-Ethy1-;8,y-dimethybbutyrolactone t'y-l3imethyl-butyrolactone;

we hy bi tyro ectqn a,a-Dimethyi a-yaleroiactone; 5,13-Dimethyl6-valerolactone; y-Diethyl-butyrolactone; o-Methylpyrrolidone ('y-valerolactam); p-Methyl-piperidone; etc.

Preferably the solvent mixture contains from 10 to 50% by weight of the additional solvent. In certain circumstances the upper limit can be exceeded since even then a certain improvement in solubility is obtained.

The examples given below describe in more detail individual mixtures which have particularly good properties due to the nature and pmportions of their ingredients.

When more than one of"the said "additional substances are admixed with tetrahydrofurane, which is possible according to this invention; preferably the proportions of the ingredients are maintainedjwithin the aboye described limits. the total quantity of the additionai vsubstances lying within these limits. I V

The favorable 'eiieets in improving the solubility with the solven mixtur ll g a c to the invention are obtained not only with polyvinyl chloride but also with copolyrners oi vinyl chloride, ior example vinyl chloride-vinyl aceat e p y ers, v nyl ch qride-vi y dene chloride copoylmers, vinyl chloride-styrene copolymere, vinyl chloride-vinyl acetate-vinylidcne ide enql mers e et One of the most important advantages of solutions produced according to the invention is that the solutions can bespujn' without difiiculty at room temperature to form artificial threads, artificial bristles and the like, i'therby the wet spinning process 'o'r'by thedr'y spinning process. In this way for sxampleurtificial threads are ob taine d with a strengthoff 215 to 3 "grams/denier and extensions of "-25%. The solutions are also very suitable for the production of films by casting; The s'olutions preferably contain from about 15 to about 25% by weight of polymer.

The following examples de'scr-ib'e, solely by way of illustration, presently "preferred embodiments of the process "of 'the'mvention:

Example l 210 parts by weight of polyvinyl chloride are introduced with stirring at G. into a mixture of l50 parts by'wei'ght of butyrolactone and 500 parts by weight of tetr'ahydrofurane. The mixture is heated to boiling while stirring and, when solution is complete, is cooled to 20? C... The resultant solution can be spun, for example, through multi-hole stainless steel jets, into water at 209 ,r

Example 3 100 parts by weight of polyvinyl chloride are introduced with stirring at C. into a mixture of 100 parts by weight of N-methylpyrrolidone and 400 parts by weight :of tetrahydrofurane. The mixture is heated to boiling and then cooled again to room temperature (about 20 0.). The resulting solution can be spun into water. at 20". C.

Example 3 100 parts by weight of, polyvinyl chloride are introduced with stirring at 25 C. into a mixture of 80 parts by weight of glycol carbonate and 400 parts by weight of tetrahydrofurane, the mixture heated to boiling in the course of 36. minutes and, when complete solution has taken place, cooled again to 20 Q. The resultant 50- 4 lution is then ready for spinning or casting, after le-f n t e dete t ii eemi Example 4 parts by weight of a copolymer from equimolecular" amounts of vinyl chloride and acrylonitrile are introduced with stirring at 25 C. into a mixture of 80 parts by weight of butyrolactone and 420 parts by weight of tetrahydrofurane. The mixture is brought to boiling in the'cou'rse' of 45 minutes and, when solution is complete, is cooled to about 20 C. The product is then ready for use in preparing threads, films,

etc.

The butyrolactone may with equivalent results be replaced, in this example, by an equivalent quantity or e-caprolactam, N-isopropyl-pyrrolidone or ycaprolactone, while otherwise proceeding as described.

En emble 5 parts y wei ht of polyvinyl hloride are introduced with stirring at :20? G. into a mixture of 50 parts y w i ht of u yr la to e and .500 parts by wei ht of tet ah dro urane. the mixt r heated in order to e e solution and, when lu ion is complete, eoo edaga n t 2.0? C. The resultant solution is then ready .1. spinning or casting.

The butyro ct ne may with equ valent r s t be replaced, in this exam le. by an equivalen quantity o e-c prolaet m N-ie propyl-pyrolidone or y-eapr act ne While, other-w s eceeding as described.

Example '6 120, parts by weight oi polyvinyl chloride are introduced with stirring at zll" into a mixture of parts by weight'ot butyrolactone and'375 parts by weight of tetrahydrofurangthemix ture heated to effect solution and, when solution is complete, cooled again to 20 C, The resultant solution is' then ready spinning or casting.

Example '7 '0 P rt by we h 9 nellv i yl c ri a introduced with stirring at 25f? C. into a mixture of 250 parts by weight'oi glycol carbonate and 250 parts by weight of tetrahydroiurane, the mixture eate u ti mrl e's lu f n has taken a e.- and then cooled again to 210 The resultant solution is then ready for spinning or, casting.

Having thus disclosed the invention, what is claimed is: v f

1. "A liquid composition of matter which can be spun to form threads and the like and which can be cast to form films, comprising a vinyl chloride polymer as solute in solution in tetrahydr'o'furane as solvent, said solvent having admixed therewith irom about 10% to about 50% by weight of the mixture, of an additional'solvent selected .from the group consisting of lactones and la'ctams which can dissolve polyacrylonitrile completely but whioh'do not by themselves give vinyl chloride polymer sdmtionswmehcan be spun.

2,. A liquid composition Iof matter which can be spun to form threads and the'like' and which can be cast to form n cfolnfprising'ia vinyl chloride polymer as solut in. a soliitio'n'in tetra hydrofura'ne' as solvent, said solvent having admixed therewith from about 10'.%'t0 about5.0% by weight of the mixture, of a butyrola'ctone'.

' 3. A liquid composition of matter which can be spun'to form threads and the like and which an be. ast it as, eo s n vinyl chloride polymer as solute in solution in tetrahydrofurane as solvent, said solvent having admixed therewith from about to about 50% by weight of the mixture, of butyrolactone.

4. A liquid composition of matter which can be spun to form threads and the like and which can be cast to form films, comprising a vinyl chloride polymer as solute in solution in tetrahydrofurane as solvent, said solvent having admixed therewith an additional solvent selected from the group consisting of lactones and lac tams, the proportion between additional solvent and tetrahydrofurane in the solvent mixture being about 1:3 by weight.

5. A liquid composition of matter which can be 6 valerolaotone and tetrahydrofurane in the solvent mixture being about 1:3 by weight.

7. A liquid composition of matter which can be spun to form threads and the like and which can be cast to form films, comprising a vinyl chloride polymer as solute in solution in tetrahydrofurane as solvent, said solvent having admixed therewith glycol carbonate, the proportion between glycol carbonate and tetrahydrofurane in the solvent mixture being about 1:3 by weight.

8. A liquid composition of matter which can be spun to form threads and the like and which can be cast to form films, comprising a vinyl chloride polymer as solute in solution in tetrahydrofurane as solvent, said solvent having admixed therewith e-caprolactam, the proportion between e-caprolactam and tetrahydrofurane in the solvent mixture being about 1:3 by weight.

ERWIN HEISENBERG. JOHANNES KLEINE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,529,449 Ham Nov. 7, 1950 

1. A LIQUID COMPOSITION OF MATTER WHICH CAN BE SPUN TO FORM THREADS AND THE LIKE AND WHICH CAN BE CASE TO FORM FILMS, COMPRISING A VINYL CHLORIDE POLYMER AS SOLUTE IN SOLUTION IN TETRAHYDROFURANE AS SOLVENT, SAID SOLVENT HAVING ADMIXED THEREWITH FROM ABOUT 10% TO ABOUT 50% BY WEIGHT OF THE MIXTURE, OF AN ADDITIONAL SOLVENT SELECTED FROM THE GROUP CONSISTING OF LACTONES AND LACTAMS WHICH CAN DISSOLVED POLYACRYLONITRILE COMPLETELY BUT WHICH DO NOT BY THEMSELVES GIVE VINYL CHLORIDE POLYMER SOLUTIONS WHICH CAN BE SPUN. 